The present invention relates to an improvement in a supporting structure of an operator cab for a work machine, such as a bulldozer, wherein a supporting structure for an operator cab is mounted on a floor frame which has a front portion and rear portion different in height.
Work machines, particularly bulldozers, are mainly used in earth work on irregular ground. The body of a work machine is subject to a large vibration during vehicle travel. A supporting structure is generally mounted between a body frame of a work machine and its operator cab to prevent the vibration from transiting to the latter through the former, which results in providing the operator with a great comfort in the cab and a stable operator posture during operation.
U.S. Pat. No. 5,498,060 issued on Jun. 18, 1999, assigned to the assignee of the present invention, discloses a floor frame supporting structure of a work machine such as bulldozers. As shown in FIG. 19, a cab 41 is mounted on a floor frame 42 having substantially Z-shaped configuration including a front portion and a rear portion which is high than the front portion. A front right side portion and a front left side portion of the floor frame 42, as shown in FIG. 20, are respectively coupled to the body frame 43 through buffer support means 44, 44, which are supported ally in a direction of pitching movement through rubber bushings 44A, 44A on periphery of shafts 44B, 44B mounted pivotally to the floor frame 42. The rear right side portion and the rear left side portion of the floor frame are respectively supported by the supporting structures, which absorb vibration in the vertical and transversal directions, to a pair of brackets 46, 46 fixed to the body frame 42. The supporting structure as shown in FIG. 21 comprises a multi-layer rubber mount viscous damper 45 including a tubular resilient cushion member 47 such as rubber or plastics, a damper plate 49 and non-compressive damper oil 48 in a chamber, and are respectively secured to the front left side portion and the rear left side portion of the floor frame 42 so as to absorb transversal and vertical shock loads from the body frame 42.
Another Japanese utility model application application No. 1989-99776 applied on Oct. 27, 1988 assigned to Kubota Tekko in FIG. 22, discloses that at least one of front side portions and rear side portions of a floor frame are respectively coupled to a body frame through rubber or plastics front or rear buffer support means 53F, 53R in FIG. 23 including rubber mount members 56, 56 having a truncated cone configuration in FIG. 24. Each axis of the supporting structures are respectively oriented at an angle within the range from the their central axis so as to orient toward the center of gravity of a operator cab in the transversal direction and longitudinal direction of a work machine.
There are drawbacks associated with these convention technology described above.
U.S. Pat. No. 5,498,060 discloses that since the rubber bushings 44A, 44B of the buffer support means 44, are needed to have a sufficient rigidity to absorb vibration generated in vertical direction at the low floor portion. The rubber bushing 44A, 44B can provide an insufficient damper effect to absorb a vertical heavy shock load, such as is caused when the work machine runs over an obstruction. With such a problem, vertical vibration of the operator cab is converted to pitching movement with respect to a shaft of the buffer support means 44. This pitching movement is absorbed by the buffer support means 45R secured to a high both side portions of the floor frame. However, since the high both side portions of the floor frame 42 are subject to pitching movement with respect to the shaft of the buffer support means 44 e.g. the rubber mount viscous dampers 45 can receive not only the shock load in the vertical direction, but also the that in the longitudinal direction of a work machine. In order to prevent from a transversal motion or rolling motion of the operator cab, a transversal spring constant of the rubber mount or the tubular rubber cushions 47 in the perpendicular direction to the support axis thereof is set to hard. Similarly, the rigidity of the tubular rubber cushions 47 in the longitudinal direction of a work machine is stronger than that in the vertical direction, e.g. the transversal movement thereof is restricted.
Therefore, the rubber mount viscous damper involves a problem in that a vertical shock load, such as is caused when the work vehicle runs over an obstruction, cannot be sufficiently absorbed by pitching movement centering around the axis of a shaft 44B.
The buffer support means 53F, 53R disclosed in U.S. Pat. No. 5,498,060 are respectively located at positions which are approximately as high as the height of each other and the support axis thereof is inclined at a angle xcex8 to the vertical axis toward the center of gravity in the longitudinal and transversal directions so as to prevent from transversal movement of the operator cab. However, in the case that the buffer support means 53F, 53R are positioned apart from a operator cab, this invention involves problems in that the operator cab has a large displacement during longitudinal and transversal motion.
The present invention is directed to overcoming one or more of the problems described above.
Therefore it is an object of the present invention to provide such a supporting structure of an operator cab of a work machine so as to have a great absorption for accommodating a vertical movement and pitching movement from the body frame of work machine to the operator cab.
In a supporting structure for an operator cab on a body frame of a work machine, having a floor frame, the operator cab being mounted on the floor frame which has a low floor portion and a high floor portion spaced longitudinally from each other at a forward location and a rearward location in a side view, and a plurality of vibro-isolating support means being provided between said low and high floor portions and said body frame so as to support the operator cab resiliently, at least one of said vibro-isolating support means located at the low floor portion and the high floor portion having a support axis which inclines longitudinally at a predetermined angle (xcex8) from vertical axis toward the center of gravity (G).
Since lateral and longitudinal rigidity of the supporting structure can be varied depending on a inclination angle from a vertical axis at which they are secured to a bracket fixed to the body frame, setting a suitable inclination angle of the supporting structures can bring an optimum responsibility or damping effect for vertical movement, pitching movement, transversal movement and rolling movement from the body frame to the operator cab.
In a supporting structure for an operator cab on a body frame of a work machine having a floor frame including a low floor portion and a high floor portion spaced longitudinally from each other in the longitudinal direction of a work machine, a vibration mode in that the operator cab moves pitching movement centering around adjacent the support point of the supporting structures mounted vertically on either the front floor portion or the rear floor portion of the floor frame, provides an great important effect to absorb vibrations.
In the vibration mode, by inclining at a suitable angle the supporting structures mounted at least one of the front floor portion and the rear floor portion of the operator cab, the inclined support axis of the supporting structure, which a small rigidity or spring constant of the supporting structure is usually set to small along, is substantially coincident with the direction of vibration (line of action of a shock load) on pitching movement centering around a support point adjacent the other supporting structures.
This causes a restrain against the displacement of the supporting structure to reduce, which results in enabling the rigidity (spring constant) for the supporting structure mounted in a suitable inclination angle on pitching movement to be less than that of the supporting structure mounted vertically. This results in absorbing the inclined vibro-isolating support means effectively pitching movement to provide operator with a great comfort in the cab and his stable posture during operation. It should be noted that a rigidity in the direction along the perpendicular axis to the support axis of the inclined supporting structure is set to be large, for example, more than ten times that in the direction along the latter axis.
Further yet, in a supporting structure for an operator cab on a body frame of a work machine, having a floor frame, the operator cab being mounted on the floor frame which has a low floor portion and a high floor portion spaced longitudinally from each other at a forward location and a rearward location in a side view, and a plurality of vibro-isolating support means being provided between said low and high floor portions and said body frame so as to support the operator cab resiliently, at least one of said vibro-isolating support means located at the low floor having a support axis and the high floor portion having a support axis which inclines longitudinally with angles from 10 degrees to 20 degrees from a vertical axis toward the center of gravity (G) of the operator cab.
A maximum shock load and vibration, such as is caused when most of machines run over an obstruction, can be effectively absorbed by the vibro-isolating support means which support the floor frame in the predetermined angle from the vertical direction in the longitudinal direction of a work machine. An operator cab for a work machine such as a bulldozer is normally subject to a maximum shock load, such as is caused when the machine runs rearward over an obstruction. A line of action of the shock load inclines longitudinally within the range substantially from 10 degrees to 20 degrees from vertical axis. Accordingly, the vibro-isolating support means is desirably mounted so that the inclined support axis thereof is substantially coincident with a line of action of a shock load. This brings a great efficient absorption to reduce the heavy shock load.
Further yet, in a supporting structure for an operator cab on a body frame of a work machine, having a floor frame, the operator cab being mounted on the floor frame having a low floor portion and a high floor portion spaced longitudinally from each other at a forward location and a rearward location in a side view, and a plurality of vibro-isolating support means being provided between said low and high floor portions and said body frame so as to support the operator cab resiliently, at least one of said vibro-isolating support means located at the low floor portion and the high floor portion having a support axis which inclines longitudinally at an adjustable angle from a vertical axis toward the center of gravity (G) of the operator cab.
Since the angle (xcex8) can be varied by adjusting manually within the predetermined range, the identical supporting structures can be easily adopted to use relative to a various kind of work applications by adjusting manually the inclination angles thereof.
Further yet, in a supporting structure for an operator cab on a body frame of a work machine, having a floor frame, the operator cab being mounted on the floor frame which has a low floor portion and a high floor portion spaced longitudinally from each other at a forward location and a rearward location in a side view, and a plurality of vibro-isolating support means being provided between said low and high floor portions and said body frame so as to support the operator cab resiliently, at least one of said vibro-isolating support means located at the low floor portion and the high floor portion having a support axis which inclines longitudinally at a predetermined angle (xcex8) from a vertical axis toward the center of gravity (G) of the operator cab, the supporting structures in use are identical in all.
This lead to minimize the kind thereof and to utilize in common for all application, resulting parts management, manufacturing cost and maintenance cost can be improved remarkably.
Further yet, in a supporting structure for an operator cab on a body frame of a work machine, having a floor frame, the operator cab being mounted on the floor frame which has a low floor portion and a high floor portion spaced longitudinally from each other at a forward location and a rearward location in a side view, and a plurality of vibro-isolating support means being provided between said low and high floor portions and said body frame so as to support the operator cab resiliently, at least one of said vibro-isolating support means located at the low floor portion and the high floor portion having a support axis which inclines longitudinally at a predetermined angle (xcex81) from a vertical axis toward the center of gravity (G) of the operator cab and also disposes at the high floor portion of the floor frame so that their support points (P2) are approximately positioned adjacent Seat Reference Point for operator or the center of gravity (G) of the operator cab in the vertical direction.
Since vertical movement may minimize rolling motion centering round the Seat Reference Point or the center of gravity of the operator cab, the resulting small movement provides a great absorption effect to accommodate vibration due to a heavy shock loads. This permits operator to operate in less fatigue.
Further yet, in a supporting structure for an operator cab on a body frame of a work machine, having a floor frame, the operator cab being mounted on the floor frame which has a low floor portion and a high floor portion spaced longitudinally from each other at a forward location and a rearward location in a side view, and a plurality of vibro-isolating support means being provided between said low and high floor portions and said body frame so as to support the operator cab resiliently, at least one of said vibro-isolating support means located at the low floor portion and the high floor portion having a support axis which inclines longitudinally at a predetermined angle (xcex8) from a vertical axis toward the center of gravity (G) of the operator cab and also disposes at the high floor portion of the floor frame so that their support points P2,P2 are approximately positioned adjacent Seat Reference Point for operator or the center of gravity (G) of the operator cab in the vertical direction, the angles are set within the range substantially from 10 degrees to 20 degrees.
Vibration due to a heavy shock load, such as is caused when the vehicle runs over an obstruction, can be effectively absorbed by coupling the supporting structures between the floor frame and the body frame in the predetermine angles from a vertical axis in the longitudinal direction of the work machine.
Further yet, in a supporting structure for an operator cab on a body frame of a work machine, having a floor frame, the operator cab being mounted on the floor frame which has a low floor portion and a high floor portion spaced longitudinally from each other at a forward location and a rearward location in a side view, and a plurality of vibro-isolating support means being provided between said low and high floor portions and said body frame so as to support the operator cab resiliently, at least one of said vibro-isolating support means located at the low floor portion and the high floor portion having a support axis which inclining longitudinally within the range substantially from 10 degrees to 20 degrees from a vertical axis toward the center of gravity (G) of the operator cab and also disposing at the high floor portion of the floor frame so that their support points P2, P2 are approximately positioned adjacent Seat Reference Point for operator or the center of gravity (G) of the operator cab vertically, the supporting structures are identical in all.
This can lead to minimize the kind thereof and utilize in common for all work condition, the resulting parts management, manufacturing cost and maintenance cost can be improved remarkably.
Further yet, in a supporting structure for an operator cab on a body frame of a work machine, having a floor frame, an operator cab being mounted on said floor frame, said floor frame having a low floor portion and a high floor portion spaced longitudinally from each other at a forward location and a rearward location in a side view, and a vibro-isolating support means being provided between said low and high floor portions and said body frame so as to support the operator cab resiliently, either one of said vibro-isolating support means located at the low floor portion has a vertical support axis (Mxe2x80x94M) or the high floor portion has a vertical support axis (Nxe2x80x94N), another vibro-isolating support means has a support axis which inclines longitudinally at a predetermined angle (xcex81) from a vertical axis and also inclines laterally at a predetermined angle (xcex82) from a vertical axis toward the center of gravity (G) of the operator cab.
Since a lateral and longitudinal rigidity of the vibro-isolating support means in the vertical, lateral and longitudinal directions can be varied depending on the both angle (xcex81), (xcex82) from a vertical axis, the determination of a suitable angle provides an optimum responsibility, that is to say, damping effects for vertical movement of the operator cab, pitching movement, transversal movement and rolling motion of the work machine.
In the operator cab of the work machine, having a floor frame which including the low floor portion and the high floor portion in the longitudinal direction of the work machine, Vibration mode in that pitching movement around adjacent the supporting centers of the vibro-insolating support means have an important roll for a damping effect. In this vibration mode, by locating the vibro-isolating support means at position adjacent the center of vertical pitching movement and another inclined vibro-isolating support meanss toward the center of gravity in the longitudinal, the direction along the inclined support axes of the vibro-isolating support means are substantially coincident with the direction of vibration or a line of operation of a shock load at the support point on pitching movement. The rigidity of the direction extending along the inclined support axis is generally set small.
This causes a restrain against the displacement of the supporting structure to reduce, which results in enabling the rigidity (spring constant) for the supporting structure mounted in a suitable inclination angle on pitching movement to be less than that of the supporting structure mounted vertically. This results in the inclined vibro-isolating support means absorbing effectively pitching movement. Furthermore, the rigidity extending along the axis of a shaft can help to reduce that with respect to the lateral motion and the rolling motion. The resulting high damping effect provides an improved comfort in the cab to operate and a stable operator posture during performing operation by inclining the vibro-isolating support means toward the center of gravity of the cab in a transversal direction,
Further jet, in a supporting structure for an operator cab on a body frame of a work machine, having a floor frame, an operator cab being mounted on said floor frame, said floor frame having a low floor portion and a high floor portion spaced longitudinally from each other at a forward location and a rearward location in a side view, and a vibro-isolating support means being provided between said low and high floor portions and said body frame so as to support the operator cab resiliently, either one of said vibro-isolating support means located at the low floor portion has a vertical support axis or the high floor portion has a vertical support axis, another vibro-isolating support means has a support axis which inclines longitudinally at a predetermined angle (xcex81) from a vertical axis and also inclines laterally at a predetermined angle (xcex82) from a vertical axis toward the center of gravity (G) of the operator cab. The supporting structures in use are identical in all.
This can lead to reduce the kind thereof and achieve a common use for various applications, the resulting parts management, manufacturing cost and maintenance cost can be improved remarkably.